The invention discloses a method for machining a plurality of reverse stepped holes in a plane. The method comprises the following steps: making a surface hole machining drill jig, and prefabricating two positioning holes and guide holes which correspond to each reverse stepped hole to be machined in the surface machining drill jig; positioning the surface hole machining drill jig on a workpiece to be machined through the positioning holes by using positioning pins, locking and fixing; molding the primary through hole of each reverse stepped hole under the guidance of the guide holes; inserting the shank of a reverse milling cutter into the primary through hole from the inner side of each reverse stepped hole of the workpiece to be machined, and starting a driving main shaft to drive the reverse milling cutter to revolve and move towards the outer side along the axial direction of each primary through hole in order to mold an inner side stepped hole of each reverse stepped hole. Through the method, the high and severe machining requirements on narrow operating space, high accuracy, plurality of holes, plurality of hole diameters, machining of the reverse stepped holes and the like are met easily, the effects of high adaptability, high operability, high machining accuracy and high machining efficiency are achieved, and an entire set of machining scheme of a proprietary technology is formed.